ELECTRO-CHEMICAL PRINCIPLES. \$J 



reflections upon this object, obliges me, at present, to change positive attach 

 these denominations for each other. I shall, therefore, here- *? the ne g a ~ 

 alter call those bodies electro-positive which are collected round tro-negative to 

 the negative pole, and those electro-negative which are collected the positive 

 round the positive pole. With regard to the alectro-chemical ^° - 

 relations of bodies mutually, I shall divide them into five diffe- 

 rent classes. 



1. Absolutely electro-negative ; oxigen alone. l. Absolutely 



2. Electro-negative in general ; all combustible bodies electro-nega- 

 which produce acids with oxigen, are constantly collected at ' 



the positive pole of the pile. To this class the metalloids be- gative. 

 long, and among the metals arsenic, molybdena, and wolfram. 



3. Bodies of a variable electro-chemical nature. This class 3. Variable, 

 includes (a) such bodies as, when combined with oxigen, 



are electro-positive with regard to the preceding class, but 

 electro-negative with regard to the bodies which constitute the 

 last of the subsequent classes ; (b) such bodies as, in one degree 

 of oxidation, constitute a saline base, and in another degree 

 an acid. Tellurium is an example of the first, and antimony 

 of the latter. 



4. Indifferent. Oxided bodies, which possess no decided 4. indifferent 

 character, being neither acid nor saline bases. Such are the 



oxides of tantalium and of silicium. This class likewise 

 includes the combinations of acids with saline bases, that is to 

 say, the salts. 



5. Electro -positive. Combustible bodies and their oxides, 5. Electro-pn- 

 which, during the action of the pile, are never collected round sitiv *- 



the positive pole, and of which a great part, when combined 

 with oxigen in excess, instead of forming acids, produce super- 

 oxides. Such are potassium, baritium, lead, silver, &c. 



It is proved by experiment, that the more opposite the elec- ^ ut [J*? affi " 

 tro-chemical nature of two bodies is, the stronger in general is stronger, the 



their mutual affinity. A combustible body consequently tends more opposite 



r , . . , . , . . the electro- 



wilh greater force, to combine with oxigen, than with any c h em ical na- 



other combustible body with which it may have affinity. Hence tureof bodies 



we may conclude, that, if it were possible to obtain pure oxi- w m un -^ e 



gen in the solid form, and if, in that state, it were put into con- strongly with 



tact with a combustible body, it would become much more 0XI S CU > 



strongly electric than, for instance, sulphur with copper, and 



would, in, fact, produce, in combining with the combustible an <* produce 



body, 



